1
AIPMT 2011 Mains
MCQ (Single Correct Answer)
+4
-1
The half-life of a substance in a certain enzyme-catalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mg L$$-$$1 to 0.04 mg L$$-$$1 is
A
414 s
B
552 s
C
690 s
D
276 s
2
AIPMT 2011 Mains
MCQ (Single Correct Answer)
+4
-1
The rate of the reaction :   2N2O5 $$ \to $$ 4NO2 + O2
can be written in three ways.

$${{ - d\left[ {{N_2}{O_5}} \right]} \over {dt}} = k\left[ {{N_2}{O_5}} \right]$$

$${{d\left[ {N{O_2}} \right]} \over {dt}} = k'\left[ {{N_2}{O_5}} \right];\,\,$$ $${{d\left[ {{O_2}} \right]} \over {dt}} = k''\left[ {{N_2}{O_5}} \right]$$

The relationship between k and k' and between k and k'' are
A
$$k' = 2k ;  k'' = k$$
B
$$k' = 2k ;  k'' = k/2$$
C
$$k' = 2k ;  k'' = 2k$$
D
$$k' = k ;  k'' = k$$
3
AIPMT 2011 Mains
MCQ (Single Correct Answer)
+4
-1
A solution contains Fe2+, Fe3+ and I$$-$$ ions. This solution was treated with iodine at 35oC. Eo for Fe3+/Fe2+ is + 0.77 V and Eo for I2/2I$$-$$ = 0.536 V.
The favourable redox reaction is
A
I2 will be reduced to I$$-$$
B
there will be no redox reaction
C
I$$-$$ will be oxidised to I2
D
Fe2+ will be oxidised to Fe3+
4
AIPMT 2011 Mains
MCQ (Single Correct Answer)
+4
-1
A 0.1 molal aqueous solution of a weak acid is 30% ionized. If Kf for water is 1.86oC/m, the freezing point of the solution will be
A
$$-$$0.18oC
B
$$-$$0.54oC
C
$$-$$0.36oC
D
$$-$$0.24oC
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